Metabolism maize model

In order to estimate the flux through the SMM cycle and to explore its function, a computer model of methionine metabolism in mature Arabidopsis rosette leaves was developed based on data from radiotracer experiments and on metabolite contents. This model suggested that the cycle serves to stop accumulation of AdoMet, rather than to prevent depletion of free methionine, as proposed by Mudd and Datko.54 Because plants lack the AdoMet feedbacks on MTHFR and AdoMet synthetase that regulate AdoMet pool size in other eucaryotes, the SMM cycle may be the main mechanism whereby plants achieve short-term control of AdoMet level. MMT knockouts of maize and Arabidopsis recently became available, and these can now be used to further investigate the role of the SMM cycle, and to test the predictions of the model. 

Maize mutants with altered flavonoid metabolism can also be identified based on variation in color, either of the seeds, the vegetative parts of the plant, or the floral structures (anthers and silks). Petunia (Petunia hybrida) and snapdragon (Antirrhinum majus) have also been widely used as model species for the elucidation of flavonoid biosynthesis (reviewed by Winkel-Shirley, 2001). In the description of genes involved in flavonoid biosynthesis presented in this section, the emphasis will be on maize and Arabidopsis. 

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